Conventional techniques for obtaining information regarding elemental composition of a sample that includes fissile material are time consuming and require a laboratory environment. With more particularity, an exemplary conventional technique requires that a sample be dissolved in a solvent, and subsequently the dissolved sample is analyzed to acquire information about the elemental composition thereof. Further, conventional techniques that use active neutron interrogation to acquire information about elemental composition of samples that comprise non-fissile materials are not readily adaptable for use in obtaining information about elemental composition of samples that include fissile materials. This is because when a sample that includes fissile material is actively interrogated with neutrons, delayed gamma rays are produced, causing difficulties in isolating inelastic pre-fission gamma rays.